Los Angeles (AFP)
The thousand-year-old redwoods of California are witnesses to this: to save the forests from the increasingly frequent and violent fires which devastate the American West, it is sometimes necessary to fight evil with evil.
In this case by fire.
"It sounds a little strange to say, but it's been a century since there haven't been enough fires in California," says Rebecca Miller, a researcher at the University of Southern California (USC) in Los Angeles.
"For most of the 20th century, public policy banned all fires in California because it was mistakenly believed to be bad for the environment," she says, pleading for increased remedies. to controlled burns.
Practiced in an ancestral way by the Amerindian tribes of the region, these burns are intended to thin out the undergrowth by consuming brush and dead trunks that have fallen to the ground, so many fuels that can fuel the intensity of forest fires.
The advance of the flames was notably able to be slowed down thanks to the "controlled fires which have been prescribed during the last 25 to 30 years", according to Mark Garrett, spokesman for the Californian firefighters.
"This is the best tool we have," said the firefighter, favorable to this strategy.
The flames approached only 30 to 40 meters from "General Sherman", whose base had been wrapped in a protective fire blanket.
Unheard of, according to Mark Garrett.
"The problem is that there are thousands of square kilometers that have not been treated" by prescribed burns in the Sierra Nevada, the only place in the world where giant sequoias grow, he laments.
Low-intensity fires are generally not enough to harm these extraordinary trees, naturally adapted to these disasters with their very thick bark and the first branches that can grow thirty meters high, out of the reach of the flames.
Practiced in an ancestral way by the Amerindian tribes of the region, these burns are intended to clear up the undergrowth by consuming brushwood and dead trunks fallen to the ground, so many fuels that can fuel the intensity of forest fires Patrick T. FALLON AFP
On the contrary, these trees, some of whom are 2,000 to 3,000 years old, need fires to reproduce: the heat of the flames bursts the cones that have fallen to the ground like popcorn to release hundreds of seeds.
These giants, which only grow in California, are on the other hand not adapted to the more intense fires that have tended to break out in recent years thanks to climate change.
- Panacea?
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However, the practice of prescribed fires is not unanimous.
Low intensity fires are generally not sufficient to harm redwoods, naturally adapted to these disasters with their very thick bark and the first branches that can grow to thirty meters high, out of the reach of the flames Patrick T. FALLON AFP
"It is not an effective strategy and it has been overestimated," says environmentalist George Wuerthner.
In his eyes, the main flaw in burnout is that it must be implemented very regularly if it is to be effective.
"Since you can't reshape the landscape with such frequency, it's a bit misleading to present it as a panacea against large-scale fires," he said.
The expert also points to the impact that these prescribed fires can have if they flare up due to a change in weather conditions, not to mention smoke pollution.
For Andy Stahl, of the NGO Forest Service Employees for Environmental Ethics, "the biggest challenge is the cost".
"We're talking about millions of dollars, billions. And it's not as if we had to do that once a century. You have to start over every five or ten years," he said.
"Therefore, no one in the western United States is carrying out controlled burns in sufficient quantity to make a difference on fires", except at a very local level such as in Sequoia National Park, assures this former employee of the forestry office.
Rebecca Miller believes that financial and logistical obstacles can be overcome if a legal framework is put in place conducive to controlled burning.
The giant sequoias, which only grow in California, are among the largest trees in the world Patrick T. FALLON AFP
A reform eagerly awaited by Mark Garrett on the fire front.
"We need more money and staff. We must do these burns in the mountains, on federal lands and on private land," insists the spokesperson for the firefighters.
© 2021 AFP